CRUCIFERAE (MUSTARD FAMILY) 
693 
^.Petals white; ovaries and silicles glabrous to minutely short-pubes- 
cent. . . h. 
A. Biennials (rarely short-lived perennials) with lower leaves of ro- 
sette shriveling soon after an thesis; subspherical rosette of 1st 
year loosening and elongating to form many-leaved flowering 
stem; axis of raceme and pedicels densely pilose-tomentulose to 
villous 6. 
A.Perennials; branches of caudex usually with fibrous shreds of old 
leaves at summit, below living rosette; new rosettes well devel- 
oped at flowering time; axis of raceme and pedicels glabrous, 
sparsely hirtellous or stellate-pubescent. . . i. 
i.Foliage with all or many of its hairs simple or elongate and ir- 
regularly forking, with or without admixed stellate hairs. 
. . y. 
/.Siliques linear to linear-lanceolate, 2-2,5 mm. broad; sepals 
0.4-0. 9 mm. broad; rosette-leaves linear-oblanceolate, 1-5 
mm. broad; cauline leaves lanceolate, 1.5-6 mm. broad. . 7. 
y.Siliques elliptic to oblong-lanceolate, mostly 2.5-4 mm. broad; 
sepals 1-2.3 mm. broad; rosette-leaves oblanceolate to nar- 
rowly obovate, up to 9 mm. broad; cauline leaves oblong to 
ovate, 3—11 mm. broad. 
Posette-leaves narrowly oblanceolate, hispid with many 
simple or elongate and furcate hairs; cauline leaves ovate; 
mature central racemes from one-third to nearly full 
height of plant; sepals 1-1.5 mm. broad 8. 
Rosette-leaves cuneate-oblaneeolate, with numerous stellate 
and several-few simple and elongate furcate hairs; cauline 
leaves oblong; mature central raceme one-fourth to one- 
half full height of plant; sepals 1 .3-2.3 mm. broad. . . 9. 
£. Foliage with close stellate pubescence forming, at least on ex- 
panding leaves, a pannose coat; simple trichomes wanting or 
only rare (except as cilia) on the rosette-leaves. . . k . 
A. Silicles plump, glabrous; sepals 1.5-2 mm. long, 1 mm. broad; 
seeds closely but irregularly imbricated, often turned ob- 
lique to septum 10. 
A. Silicles strongly flattened (rather plump in no. 13, with densely 
tomentulose valves); sepals 2-3.5 mm. long, 1-2.3 mm. 
broad; seeds not imbricated, lying flat against septum. 
. . 1 . 
Z.Silicles glabrous or only sparingly hirtellous or scabrous, 
strongly flattened; racemes usually bractless. . . in. 
77i. Cauline leaves mostly rounded at base; mature siliqueB 
definitely veiny, usually flat; style obsolete or thick and 
short (up to 0.5 mm. long) ; fruiting pedicels stoutish, 
short, the lowest 1-6 mm. long. 
Stems hirsute, especially on lower internodes, with 
abundant simple divergent trichomes overtopping 
the stellate hairs; cauline leaves 6-25 (average 10). 9. 
Stems closely stellate-pannose, sparsely or not at all 
hirsute below; cauline leaves 1-8, rarely -14 (av. 4). 11. 
m.Cauline leaves narrowed or only slightly rounded at base; 
mature siliques scarcely or only obscurely veiny, often 
twisted, very thin; style slender, 0.5-1 mm. long; fruit- 
ing pedicels slender, lowest 3-15 mm. long 12. 
Z.Silicles densely stellate-tomentulose, only slightly com- 
pressed; racemes usually loafy-hracted at base. . . . 13. 
/.Flowering stem with strongly divergent branches; leaves laciniate or 
subpectinate ; style filiform, 1.5-3 mm. long, one-fourth to one-third 
as long as spirally twisted stellate- pubescent silique 14. 
e.Dwarf annuals or biennials with bractless racemes; flowering stems leafy or 
at least with one pair of leaves above the base. . . n. 
n.Silicles 1.7-6 mm. long, 6-16-seeded; petals (when developed) 2-3 mm. 
long; stems simple, or branching nearly to summit, with the numer- 
ous small leaves strigose with variously forking trichomes. 
Stems with abbreviated coryrnbiform branches from the middle and 
D. incana. 
D. clivicola. 
D. norvegica. 
D. laurentiana. 
D. pycno- 
sperma. 
D. lauren- 
tiana. 
D. glabella. 
D. arabisans. 
D. lanceolata. 
D. ramosis- 
sima. 
